The treatment of snow and ice covered roadways has included devices for the pre-treatment and treatment of road surfaces in connection with the accumulation of snow or ice thereon. Response time is especially important as winter storm conditions can change quickly. The process of pre-treating roadways, also referred to as “anti-icing,” with liquid solutions before the arrival of freezing rain or snow has served to improve road surface conditions during the early stages of a storm. Once the temperature drops or heavy snowfall occurs, however, the more conventional process of spreading granular materials, such as, salt and/or sand, for example, also referred to as “de-icing,” is typically relied upon to maintain road surfaces for driving.
Conventional methods for treating snow and ice covered roadways employ the use of separate application equipment to dispense granular materials, such as salt/sand spreaders, or bulk liquid spray systems, such as skid mounted tank/sprayer systems or bulk storage tanker/trailer rigs fitted with spray booms. A conventional method for delivering both granular and liquid materials include the combination of a V-box spreader and a pre-wet system of liquid storage tanks mounted typically in a dump body or on the flatbed of a truck.
While existing systems for treating snow and ice-covered roadways provide many desirable features and advantages, there remain certain problems with these combination bodies. For example, current methods require separate vehicles or add on trailers to transport and dispense sufficient quantities of both liquid anti-icing and granular de-icing materials. Space limitations of this combination of equipment tend to limit the volume of either one or both of the de-icing and anti-icing materials. A traditional V-box spreader with a pre-wet system has insufficient capacity to store, transport, and dispense an adequate volume of liquid for anti-icing operations without sacrificing the volume of granular materials for de-icing carried on the truck. Therefore, frequent return trips to the servicing facility are required to reload depleted materials or change out equipment.
This method results in delayed or prolonged road treatment, added fuel and operator costs, and multiple pieces of equipment. For example, the conventional systems can also require an additional cost of manpower to convert the vehicles from non-ice control to granular and/or anti-icing modes. Furthermore, loss of property, or even life, can occur as a result of the delays associated with the changing of the vehicle from granular to anti-icing and back again or with operators moving from one type of truck to another.
The methods of towing trailers behind dump trucks or utilizing top heavy pre-wetting tanks attached to a spreader system can pose safety hazards for operators and travelers on the roadways.
Current methods require the use of separate or different equipment depending on air and surface temperatures, the form of precipitation, (freezing rain or snow), timing of the application (before, during or after the storm), and the method of treatment selected or best suited to the road conditions (liquid anti-icing, pre-wet granular material, or granular material only). Therefore, the need to change the equipment treating the roadways depending on the weather and/or road conditions can lead to other delays. Often, the environmental conditions better treated by anti-icing application can change in a matter of minutes to environmental conditions better treated by granular application, and vice versa.
An auger has been used to convey the materials being spread by ice control equipment, in a “tailgate spreader,” for example. However, an auger typically has a much narrower effective width, i.e., the width of the auger over which it operates to convey material, than what is readily possible with a conventional chain conveyor system. The narrower effective width of the auger results in a smaller amount of material to be distributed being exposed above the top of the conveyor itself. Materials used for ice control (including cinders, sand, salt, etc.) have a tendency to bridge over the auger and therefore interrupted/disrupted material flow can result. Also, an auger can tunnel the material adjacent to the auger, thereby defining a cylindrical cavity in the material being spread.
On the other hand, chain conveyor systems are susceptible to maintenance problems during the off-season (cold weather being typically only a few months of the year in most instances). For example, the chain can be stationary and easily rust to the point of “freezing up,” making it un-useable the following season or requiring considerable maintenance time to free up the chain. Wear can be great on a chain as all the links are exposed to the ice control material being spread. Furthermore, because each link of the chain moves, the chain conveyor system has a considerable number of moving parts which in turn require a corresponding amount of maintenance.
In addition, a chain conveyor system can provide spurts of flow associated with the flighting bars extending between the chains. Every bar brings a quantity of material followed by a period of time with less, or no, material flow. The uneven discharge flow can cause “striping” of ice control materials on the pavement and also can require the spreading of materials in amounts larger than needed to compensate for this interrupted flow characteristic.
In view of the foregoing, there exist various needs in the art. One such need is for an apparatus which provides improved capacity and integration of anti-icing and de-icing materials for winter road maintenance. Another need is for an apparatus which achieves a higher, level of efficiency and accuracy of the application.